It has long been known in the paper trade to advance a plurality of sheets, or flat tubular cartons, along a path at a predetermined normal speed of conveyance and with a normal spacing, for treatment in successive zones along the path. After passing through the treatment zones it has been known to slow down the blanks, usually by upper and lower carrier belts to cause the sheets, or cartons, to overlap each other in shingled formation for ease in loading, discharge and packaging.
In U.S. Pat. No. 2,819,079 to Beaulieu of Jan. 7, 1958, a plurality of cut sheets are speeded up by sets of lower carrier tapes to shingle, and are then further slowed by subsequent carrier tapes to shingle further before delivery to a layboy.
The following patents are also exemplary of conveyors which cause sheets, or flat cartons to overlap and shingle, usually by merely slowing the advance to cause a following sheet to overlap a preceding sheet.
U.S. Pat. No. 3,096,978 Jendrusch--July 9, 1963 PA1 U.S. Pat. No. 3,373,606 Crampton--Mar. 19, 1968 PA1 U.S. Pat. No. 3,911,800 Feldkamper--Oct. 14, 1975 PA1 U.S. Pat. No. 3,942,786 Lauren--Mar. 9, 1976